Electromagnetic device



Oct. 21, 1958 r D. A. LACE 2,357,494,

ELECTROMAGNETIC DEVICE Filed June 10, 1955 INVEN TOR. DONALD A. LACEATTORNEY United States ELECTROMAGNETIC DEVICE Donald A. Lace, Chicago,111., assignor of one-fifth to Nicholas M. Esser, Melrose Park, Ill.

Application June 10, 1955, Serial No. 514,433

16 Claims. (Cl. 200-87) This invention relates to electromagnetics andmore particularly to an electromagnetic device having improved operatingcharacteristics.

It is the principal object of this invention to provide anelectromagnetic device having optimum operating characteristics forminimum coil size and current consumption.

An outstanding feature of the present invention resides in itsadaptability to extremely minute dimensions.

These objects and additional features and advantages will become morereadily apparent as the following description proceeds taken inconjunction with the following drawings wherein:

Fig. l is a side elevation of an electromagnetic device in accordancewith this invention illustrated in connection with a striker for a bell,gong or other audible device.

Fig. 2 is an exploded view of the components of the device illustratedin Fig. 1.

Fig. 3 is a top view of Fig. 1 with the armature removed for clarity.

Fig. 4 is a side elevation schematically illustrating an electromagneticdevice in accordance with this invention in the form of a relay.

Fig. 5 illustrates an exploded view of components for a modified form ofelectromagnetic device such as that of Fig. 1.

Fig. 6 is a top assembled view of the device of Fig. 5.

Referring now more particularly to Figs. 1 to 3 of the drawings, numeral10 represents a magnetic yoke structure having a base 11, an upstandingweb 12 extending from one end of the base 11 and an upper inturnedmember 13 which lies preferably in a plane parallel to the base 11 butof considerably shorter length. The base 11 is provided with a centralbore 14, into which a reduced end 16 of the magnetic pole 17 is fitted.A pole structure is provided by preferably presecuring the pole 17 to anextension thereof 18 which preferably lies in the same plane as that ofmember 13 and which forms with the yoke 10 and the pole 17 the entireelectromagnetic circuit or structure. The reduced end 16 of the pole 17may be provided with an internally threaded bore into which a screw 19may be threaded, thereby securing the structure to the base 11 of theyoke, or it may be merely upset and peened over to so secure it.

A coil 20, in the form of a solenoid, may be placed to snuglycircumscribe the pole 17 before it is secured to the yoke 10 or the coilmay be pre-wound directly upon the pole 17 of the pole structure 16, 17,18.

Referring particularly to Fig. 3, it will be noted that the member 18 isshaped complementary to the coil 20 except for its rear edge 21, whichis straight. The edge 21 is closely spaced from the edge 22 of theinturned member 13 of the yoke structure 10 in such a manner as to forma small air gap of the order of a few thousandths of an'inch, and in thepreferred embodiment illustrated, .018". To the upstanding web 12 of theyoke there is secured by any suitable means, such as for example, screws23, a non-magnetic, armature supporting structure Patented Oct. 21, 195824. This may conveniently be formed of brass and precision shaped into'aC-shaped structure having only three walls. The upper edges 25 of thelateral sides of this structure may be sloped at a small angle withrespect to the plane of the top surfaces 13 and 18 of the magneticstructure, this angle being of the order of 1 to 5 and preferably 1. Theconnection of the non-magnetic member to the web 12 is such that thelower armature surface is always substantially tangential to the upperportion of a radius or curved pivot 26, formed in the bending over ofthe upper magnetic portion 13 from the upstanding web 12.

However, the upper edges 25 may be flat and lie in a plane parallel tothe plane of members 13 and 18. The position of the edges 25 withrespect to member 13 may be adjusted by means of the slot-like apertures29 in the cross wall of the supporting structure 24. The range ofadjustability is such that the armature position, to be describedpresently, is maintained at rest with respect to surfaces 13 and 18 atan angle of 1 to 5.

It is to be understood that the armature supporting structure 24 maycomprise any non-magnetic material and need not be metal. It maycomprise, for example, a resin or rigid plastic insulating material. Theshape may also vary and may be solid so long as the slopecharacteristics imparted thereby to the armature remain in the rangespecified.

Two aligned positioning pins 27 are provided near opposite sides of thestructure 24. The lateral walls of the structure 24 may also be providedwith one or more pairs of aligned bearing holes 28, the purpose forwhich will appear shortly.

The magnetic device is completed with an armature 30 of magneticmaterial and is substantially rectangular but may have a rounded end tomatch that of the base 11. It is provided toward its rear edge 31 with apair of notches or bores 32, which fit about the guide pins 27. It

is further provided with an intermediate aperture 33.

The armature 30, guided by pins 27, is connected to thenon-magnetic'supporting structure '24 or the yoke 10 by means of a pin35 extending through the aperture 33 and anchored at any convenientplace and by any convenient means, for example on the cross Wall of thestructure 24 by means of a threaded or hook and eye connection. Thearmature 30 is held in place under the moderate tension of a coil spring36 between the armature and the head of the pin 35 which it surrounds.In the embodiment illustrated, the spring 36 is positioned above thearmature but obviously can be positioned beneath as well. The positionof the spring may be varied but it is preferable that it be positionedcloser to the radiused pivot than to the rear pivot position of thearmature. The rear lateral sides of the armature 30 in the restposition, therefore, are supported on the top edges 25 of the armaturesupporting structure 24 so that the armature bears tangentially upon theupper portion of the radiused surface 26 of the magnetic piece 13 at asmall angle to the top surfaces 13 and 13 of the magnetic circuit andclosely adjacent the air gap. It will be apparent, therefore, that whenthe coil 20 is energized, the armature will be rocked downwardly aboutthe radiused pivot 26, immediately closing the air gap between edges 21and 22, and storing up mechanical energy in the spring 36. When thecircuit to the coil 20 is opened, the armature will move toward its restposition under the stored up energy of the spring 36 and will rock atleast one or more times about its rearmost pivot edge 31 until it comesto a rest position. If necessary, a thin non-magnetic buffer material,such as aluminum foil may be placed between the armature and surface 18to control possible sticking due to residual magnetism. Obviously, asimple self-interrupting circuit can be arranged and timed to utilizewhatever number of oscillations, preferably one, in this return rockingarrangement, .as is desired.

In the embodiment shown, a striker or clapper member 40 is attached byarms 41 to a pivot shaft 42, secured through:aligned ?bores 28 in'ithelateral walls .ofathe non-.

magnetic member 4. .A :simple' selfeinterrupted icircuit for the coil 20may he :arranged through mating ;contacts 43son the clapper Eandanzisolated contact-:37 ton-the armature. :Such a circuit isschematicallyrillustmted Fig. 1. Depending :on the operating position-of:sucha device, .a spring 44 :to bias "the clapper toward contactposition may 'be required.

The magnetic structure of ;this :device is soxefiicientr'thatconsiderable energies-can :be transferred to the =clapper member-:40 of:-such :a magnetic ;device employing an. tex

tremely minute coil. The entire coil, whether pre-wound onpole 17\orwound'asaa (solenoid and ;placed;thereover, need not exceed inaoutside :diameteruthe :diameter of.;a standard pencil eraser, :and ispreferably wound of :copper wire .ranging about 42 to '43 wire :size,-andhaving a total resistance .of 20 .to :40 ohms, :and ,preferablyn-30ohms. The length .of-the :arms 41 need notrexceed-fi inch and thisentire magnetic device, operating self-interrupted, will drive aonetounce clapper l-to ilZzQSCillEttions perzsecond at .fllCllI'IBHtconsumption lofsless than one milliampere per hour. Inctherxwords,powered'by a. single :standard ipenlight dry cell, .a magnetic device10f this type will operate continuously for;3 00 hours or :more.Thecurrent consumed in watts,:therefore, is of=thetorder of' to A ofawatt. It will be apparent thahthe compactness and efficiency of itsmagnetic circuit:lends this device particularly well to any need for amagnetic'structure, eitherself-interrupted or energized :and released atwill, especially where extremely small dimensions ;and

currents are required. The entire .devicewith clapper need not exceedthe dimensions of a OIIG-hfilfrlIlChtCllbG.

In Fig. 4 the same magnetic structure withzpairs'oi contacts- 45 and 46illustrates .schematically :extremely efficientrelay arrangements ofminutesize. InFig. 4, the insulating propertiesof a nonmetallic-mon-magnetic armature supporting :structure 24 may .be utilizedto :mount a pair:of relayecontactssuchas =46,-operated by tthe rearofithe armature30-byan arm-47.

Figs.:5 and:6rillustrate ,azmodified form of thermagnetic structure'resultingin "even greater ,efiiciencies, like mumhers being assigned tolike members.

Certain modifications and changes will 'be suggested hereby tothoseskilled in the art, and it iszintended that all snchrevisionsiand'modifications as fall within the true spirit of thisinvention'areincluded :within its scope as best defined-by the appendedclaims.

.I- claim:

1. An electromagneticdevicecomprising a yoke structure'ofmagneticmaterial having a base and.an .upstand ing web connected to oneend of the .base, awpoleifixed to the base, a coil .disposed about saidpole, :anrextensinn of said pole adjacent said yoke structure, andspaced therefrom by'a narrow -air. gap, an armature supporting member ofnon-magnetic material secured ;to1the yoke structure, and anal-mature,biasing means urging said armature toward simultaneousengagementwithtthe endssof the webdistal from thebase and a-portionatleast of said armaturesupporting-member, said armature extendingratrest'over said extensionof said pole, adapted to :rock aboutithe yokestructurezwhen lthercoil is energized and about a pivot onthe-supporting'member on'deenergiza tion of the coil.

2..An.electromagnetic device-comprising ayoke struc ture of magneticmaterial-having a base andan upstanding web connectedtoone end. of. thebase, .a pole fixed to the base, a coil disposed .aboutsaid pole,anlextensionof saidpoleadjacent said yokestructure,.andspacedtherefrom'by a narrow air gap, an'armaturesupporting member'of'non-magnetic material secured to the yokestructure, and an armature, biasing means urging said armature towardsimultaneousengagement'with'the ends olE-the 4 web distal from the baseand a portion at least of said armature. supporting member, saidarmature extending ,at rest over said extension of said pole, and at aslight angle thereto, adapted to rock about the yoke structure when thecoil is energized and about a pivot on the supporting member ondeenergization of the coil.

3. An electromagnetic device comprising a yoke structure of magneticmaterial-having a base and an upstanding web connected to one end of thebase, a pole fixed to the base, a coil disposed about said pole, anextensionof said :pole'adjacent said tyoke structure'and'spacedtherefrom by a narrow air gap, an armature supporting member ofnon-magnetic material secured to .the yoke structure, -and an armature,biasing means urging said armature toward-simultaneous engagement withthe ends of the web distal from the base and a portion at least of saidarmature supporting member, said armature extending at rest over saidextension of said pole, adapted to rock about the yokestructure when thecoil is energizedand about a pivot on the supporting member ondeenergization of the coil, the end -of theweb -distal from :saidbase'being provided with a radius -.whereby a continuous and progressivemagnetic contact -is maintained with-the armature as it rocksthereabout.

4. An electromagnetic device as claimed in claim 1, in -which saidarmature supporting member comprises an insulating material.

5. An electromagnetic device comprising a yoke'structure of magneticmaterial having a-base and anupstahding web connected to'oneend of thebase, a pole'fixed to the base, a coil disposed about said pole, *anextension of said pole adjacent said'yoke structure and-spaced therefrom-byanarrow air gap, an armaturesupporting member of non-magneticmaterial secured to' the yoke structure, and an armature, biasing means'urging said armature toward simultaneous engagement with'the "ends ofthe'web-distal from the base and a-portion at least of said armaturesupporting member, said'armature extending at rest over said extensionof said pole and at' a slight angle thereto, adapted to rock aboutthe'yoke struc ture when the coil is energized and about a pivot on thesupporting member on deenergization -ofthe"-coil, the 'position'of saidarmature supporting member being adjustable with respect to said yoke tovary the'angle of the armature at rest with respect'to the'upper-surfaceof'the extension of the pole.

6. An electromagnetic device comprising a yokestructure of magneticmaterial having a base and an'upstanding web connected to one endof'thebase, a pole fixed to'the base, a coil disposed about said pole,anextension of said pole adjacent said yoke structure and :spacedtherefrom by a narrow air 'gap, an armature supporting member ofnon-magnetic material secured 'to'the .yoke structure, and an armature,biasing means urging said armature toward'simultaneous engagement withthe ends of the web distal'from the base and a portion at least ofsaid'armature supporting member, said armature extending at rest oversaid extension of said pole, adaptedto rock about the yoke structurewhen the coil is energized and about a-pivot onthe supporting member ondeenergization of the coil, a swinging member provided with a pair ofarms straddling said yoke and coil, said member being pivotallymounted'to said armature supporting member and adapted to be struck bysaid armature to swing it about its pivotal mounting, andself-interrupted circuit means for operating said coil ,tointermittently swing-the swinging. member about its said pivotalmountmg.

7. An 'electromagnetic device comprising ayoke structureofmagneticmaterial having a base and an upstandingweb connected to one end of thebase,.a pole fixed to thebase, a coil disposed about said pole, anextension of sai'd'pole adjacentisaid yoke structure and spaced therefrom'by a narrow air gap, an armature supporting memberof non-magneticmaterial secured to the yoke structure, and an armature, biasing meansurging said armature toward simultaneous engagement with the ends of theweb distal from the base and a portion at least of said armaturesupporting member, said armature extending at rest over said extensionof said pole, adapted to rock about the yoke structure when the coil isenergized and about a pivot on the supporting member on deenergizationof the coil, and at least one pair of relay contacts operable by saidarmature.

8. An electromagnetic device comprising a yoke structure of magneticmaterial having a base and an upstanding web connected to one end of thebase, a pole fixed to the base, a coil disposed about said pole, anextension of said pole adjacent said yoke structure and spaced therefromby a narrow air gap, an armature supporting member of non-magneticmaterial secured to the yoke structure, and an armature, biasing meansurging said armature toward simultaneous engagement with the ends of theweb distal from the base and a portion at least of said armaturesupporting member, said armature extending at rest over said extensionof said pole, adapted to rock about the yoke structure when the coil isenergized and about a pivot on the supporting member on deenergizationof 'the coil, said armature supporting member comprising an insulatingmaterial, and at least one pair of relay contacts secured to saidarmature supporting member of insulating material and operable by saidarmature.

9. An electromagnetic device comprising a yoke structure of magneticmaterial having a base and an upstanding I web connected to one end ofthe base, a pole fixed to the base, a coil disposed about said pole, anextension of said pole adjacent said yoke structure and spaced therefromby a narrow air gap, an armature supporting member of non-magneticmaterial secured to the yoke structure, and an armature, biasing meansurging said armature toward simultaneous engagement with the ends of theweb distal from the base and a portion at least of said armaturesupporting member, said armature extending at rest over said extensionof said pole and at a slight angle thereto, adapted to rock about theyoke structure when the coil is energized and about a pivot on thesupporting member on deenergization of the coil, at least one surface ofthe armature supporting member and upon which the armature bears whenthe coil is deenergized being provided with a slope substantially equalto the angle at which the armature extends with respect to the extensionof said pole.

10. An electromagnetic device comprising a yoke structure of magneticmaterial having a base and an upstanding web connected to one end of thebase, a pole fixed to the base, a coil disposed about said pole, anextension of said pole adjacent said yoke structure and spaced therefromby a narrow air gap, an armature supporting member of non-magneticmaterial secured to the yoke structure, and an armature, biasing meansurging said armature toward simultaneous engagement with the ends of theweb distal from the base and a portion at least of said armaturesupporting member, said armature extend ing at rest over said extensionof said pole, adapted to rock about the yoke structure when the coil isenergized and about a pivot on the supporting member on deenergizationof the coil, the means biasing the armature toward said armaturesupporting member being positioned closer to the web than to theposition where the armature pivots on the armature supporting member.

11. An electromagnetic device comprising a yoke structure of magneticmaterial having a base and an upstanding web connected to one end of thebase, an inturned projection extending from the other end of said web inthe same direction as the base, a pole fixed to the base and having aportion extending to adjacent said inturned projection and spacedtherefrom by a narrow airgap, a coil disposed about said pole betweenthe portion extending therefrom and the base, an armature supportingmember of non-magnetic material secured to the yoke structure, and anarmature, biasing means urging said armature toward simultaneousengagement with portions at least of the inturned projection and thearmature supporting member, said armature extending at rest over saidportion extending from said pole at a slight angle thereto and adaptedto rock about the juncture of the inturned projection and the web whenthe coil is energized and about a pivot on the supporting member ondeenergization of the coil.

12. An electromagnetic device as claimed in claim 11, in which thejuncture of the web and the inturned projection is radiused whereby acontinuous and progressive magnetic contact is maintained with thearmature as it rocks thereabout.

13. An electromagnetic device as claimed in claim 12, in which the meansbiasing the armature is positioned closer to said radiused pivot than tothe position where the armature pivots on the armature supportingmember.

14. An electromagnetic device as claimed in claim 12, including aswinging member pivotally mounted to said armature supporting member andadapted to be struck by said armature to swing it about its pivotalmounting, and self-interrupted circuit means for operating said-coil tointermittently swing the swinging member about its said pivotalmounting.

15. An electromagnetic device as claimed in claim 12, including at leastone pair of relay contacts operably by said armature.

16. An electromagnetic device comprising a yoke structure of magneticmaterial having a base and at least one upstanding extension connectedto the end of the base, a pole connected to the base adjacent saidupstanding extension, a coil disposed about said pole, an extension ofsaid pole positioned adjacent said yoke structure and spaced therefromby a narrow air gap, an armature supporting member of non-magneticmaterial secured to the yoke structure, an armature, said armature beingsupported by said non-magnetic material and said yoke structure, thesaid armature extending at rest over the exten sion of said pole andadapted to rock about said nonmagnetic material and said yoke structureupon energization and deenergization of the coil, and biasing meansnormally urging said armature simultaneously against the said yokestructure and the supporting member of nonmagnetic material secured tothe yoke structure.

References Cited in the file of this patent UNITED STATES PATENTS501,183 Daves July 11, 1893 629,645 Baynard July 25, 1899 1,269,563Henderson June 11, 1918 1,360,281 Evans Nov. 30, 1920 1,891,676 LansingDec. 20, 1932 1,937,403 Davies Nov. 28, 1933 2,287,539 Spaulding June23, 1942 2,321,834 Marco et a1 June 15, 1943 2,458,939 Hall Jan. 11,1949 2,526,455 Bonnano Oct. 17, 1950 2,610,995 Orsatti et a1 Sept. 16,1952 2,617,950 Lace Nov. 11, 1952

